The protein 5-lipoxygenase-activating protein (FLAP) is associated with the pathway of leukotriene synthesis. In particular, 5-lipoxygenase-activating protein (FLAP) is responsible for binding arachidonic acid and transferring it to 5-lipoxygenase. See, e.g., Abramovitz, M. et al., Eur. J. Biochem. 215:105-111 (1993). 5-lipoxygenase can then catalyze the two-step oxygenation and dehydration of arachidonic acid, converting it into the intermediate compound 5-HPETE (5-hydroperoxyeicosatetraenoic acid), and in the presence of FLAP convert the 5-HPETE to Leukotriene A4 (LTA4).
Leukotrienes are biological compounds formed from arachidonic acid in the leukotriene synthesis pathway (Samuelsson et al, Science, 220, 568-575, 1983; Cooper, The Cell, A Molecular Approach, 2nd Ed. Sinauer Associates, Inc., Sunderland (Mass.), 2000). They are synthesized primarily by eosinophils, neutrophils, mast cells, basophils, dendritic cells, macrophages and monocytes. Leukotrienes have been implicated in biological actions including, by way of example only, smooth muscle contraction, leukocyte activation, cytokine secretion, mucous secretion, and vascular function.